1. Field of the Invention
The present invention relates to a method for the removal of volatile anesthetic agents from breathing gas in an apparatus for respirating of patients provided with a line or conduit system in which breathing gas can be circulated, comprising leading the breathing gas or a part thereof through a filtering apparatus with activated carbon, whereby the breathing gas is cooled when passing through the filtering apparatus.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
Such a method is known.
By cooling the breathing gas, for instance to a temperature below 21° C., an anesthetic agent having a boiling point below 21° C. will condense, and the activated carbon can adsorb much more than in gaseous condition.
From the European patent application EP 1 356 840 A is known a filtering apparatus with a filter element with means for adjusting the temperature of the element, for instance for the cooling of the ingoing gas or the element itself, whereby the aim is to improve the absorption by the filter of anesthetic agent. With this apparatus further means are provided to warm the gas again, whereby the warmed gas is led again through the filter and again absorbs anesthetic agent that is supplied to the patient. In this manner re-use of the anesthetic agent is possible.
This application further describes that gas intended for inhalation by a patient who is to be waken up, and which gas for this reason must not contain anesthetic agent, is led through the filter cooled, to avoid the gas absorbing anesthetic agent from the filter.
This apparatus has the drawback, that the patient is supplied with breathing gas that is cooled and that is not humid enough.
The invention aims to obviate this drawback.